Reducing Downtime with Reverse Engineering

Obtaining accurate data for reverse engineering can be challenging.

If the mine cannot halt operations long enough to allow engineers or service personnel to thoroughly inspect the area, collecting precise data while machinery is running becomes increasingly difficult.

Seeking assistance from specialized machine job shops is a viable option to manage reverse engineering and potentially avoid costly downtime. However, providing these shops with the correct data can be quite difficult, especially if sample parts cannot be supplied. There are numerous reasons for this, including:

Difficulty in removing parts from the assembly.

The mill or mine remains operational, and production cannot be interrupted.

The distance to transport parts to the specialized shop is considerable and costly.

Uncertainty about who can truly provide the necessary assistance.

Purchasing departments require multiple quotes and delivery times, yet only one part needs to be sent out.

You possess a spare part, but it has been stored for many years (often not properly maintained; for example, reducers require a decade-long moisture inhibitor and periodic turning) and it is risky to put it into service without inspection.

Parts are too large to ship, necessitating on-site assistance.

Old drawings can be helpful, but gearing requires both mating parts to mesh precisely. A common example is that the pinion will wear down much faster than the larger bull gear, even though the pinion is typically made of a harder material. Depending on the system's ratio, one tooth on a bull gear can experience many fewer cycles than each tooth of a pinion, resulting in less wear. Without data on the gearing, it becomes challenging to determine the following:

Helix pitch

Center line distance

Number of teeth (which should be straightforward, but errors can occur) – Mark each tooth!

Diameters of the parts

Basic type of gear (the easy part)

DP

Full depth of tooth

Grade of metal (can be difficult to ascertain)

Hardness of metal on tooth and on shaft.

Type of heat treatment. Induction, Carburize, flame, through harden, Nitride (also hard to determine without lab testing)

All keyway information

AGMA quality

Circular pitch and modular pitch

A good and accurate sketch or drawing showing tolerances.

If you possess accurate data on all these points, a fully integrated gear shop should be able to manufacture the gear. With missing data or data that is not easily obtainable, the manufacturing process becomes riskier. With experience and knowledge of the application, engineers can make recommended assumptions to present to the customer, allowing for a suitable part to be made.

Making a matching set also alleviates some of these issues, provided that you have accurate center distances for the gear pairs. Information such as the Helix angle will not be as critical.

The facility experiencing reducer and/or gear problems should understand what they need in terms of parts, timing, and be prepared to act swiftly. For example, any reducer built offshore and small in size is often more disposable and may be more economical to replace with a new one. This seems logical, yet we still encounter such issues. Once gear reducers exceed 250 pounds, it can be more cost-effective to rebuild them, and as the units get even larger, rebuilding becomes significantly more economical. Size matters.

At times, special circumstances will dictate the action plan, but the facility should be aware of this from the outset. Essentially, the better the data supplied, along with clear directions and expectations, the better the outcome will be for reverse engineering and delivery time. A robust maintenance plan in every facility is crucial, and having the right shops on standby to service them will result in improved timing and part quality.

Only a select few shops are equipped to handle the machining needs of mining and heavy industry. In large urban areas, more shops may be available, but from our experience, they are few and far between. Understanding your supplier's capabilities is critical to avoid delays if they, in turn, need to outsource the majority of large-scale jobs.